PSI - Issue 35

Sadik Sefa Acar et al. / Procedia Structural Integrity 35 (2022) 219–227 Sadik Sefa Acar et. al. / Structural Integrity Procedia 00 (2021) 000–000

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Von Mises equivalent stress contours for building and normal direction loadings are shown in Figs. 6 and 7 re spectively. The lower stress response for RVEs with elongated and oriented grains can also be observed in von Mises stress distributions. Moreover, as the orientation alignment is increased, due to the diminishing of the misorientations between neighboring grains, more homogeneous stress distribution is observed in Figs. 6d and 7d.

5. Conclusions

In this paper, the mechanical behavior of the microstructures with columnar grains which are observed in addi tively manufactured metallic products is investigated through a crystal plasticity framework. Columnar grain structure and the corresponding orientation alignment are numerically modeled to assess the constitutive response and the anisotropy due to additive manufacturing. Step by step, the grains are elongated and the orientations are restricted around the building direction to analyze the anisotropy at di ff erent levels. Firstly, the sole e ff ect of morphology is studied by modeling the RVEs with di ff erent degree of columnar structure having randomly oriented grains, however the di ff erence between the constitutive responses is found to be negligible. After assigning the corresponding restricted orientations to the morphologies, a significant di ff erence occurs between flow stresses of RVEs with equiaxed and columnar grains for both building and normal direction loading. The stress response weakens as grains become more columnar. RVEs with grains oriented around the building direction demon strates that when the orientation of each grain is assigned in a similar direction, the misorientation of the neighboring grains diminishes. Since the misorientations indirectly impose the e ff ect of the grain boundaries, oriented RVE shows lower resistance to plastic deformation. The numerical results agree qualitatively with the literature. Final crystalline structure of additively manufactured products have significant importance in terms of mechanical properties. Charmi, A., Falkenberg, R., A` vila, L., Mohr, G., Sommer, K., Ulbricht, A., Sprengel, M., Neumann, R., Skrotzki, B., Evans, A., 2021. 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